Topic Collection+Entry=ControlArea
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In Response to Sven2
You know, it's easy to calculate if (and when) two spheres of known position and velocity collide.
Be x0(t)=p0+v0*t the position of object one; be x1(t)=p1+v1*t the position of object two. The distance of the two is D(t)=||x0(t)-x1(t)||. The minimum distance is at d/dt D(t) = 0. Derive and resolve t (excluding any special cases of zero velocity and such here):
D(t) = sqrt((p0x-p1x+(v0x-v1x)*t )^2 + (p0y-p1y+(v0y-v1y)*t )^2)
d/dt D(t) = 1/sqrt((p0x-p1x+(v0x-v1x)*t )^2 + (p0y-p1y+(v0y-v1y)*t )^2) * (2*(p0x-p1x+(v0x-v1x)*t )*(v0x-v1x) + 2*(p0y-p1y+(v0y-v1y)*t )*(v0y-v1y)) = 0
(p0x-p1x+(v0x-v1x)*t )*(v0x-v1x) + (p0y-p1y+(v0y-v1y)*t )*(v0y-v1y) = 0
(p0x-p1x)*(v0x-v1x) + (p0y-p1y)*(v0y-v1y) = -t * ((v0x-v1x)^2+(v0y-v1y)^2)
t = -((p0x-p1x)*(v0x-v1x) + (p0y-p1y)*(v0y-v1y)) / ((v0x-v1x)^2+(v0y-v1y)^2)
This gives you the time t at which the distance of the two objects is minimal. Clamp t to 0-1 (for the duration of 1 frame) and check if D(t) is smaller than the sum of the two sphere's radius.
(math not double checked, but you should get the point)
Be x0(t)=p0+v0*t the position of object one; be x1(t)=p1+v1*t the position of object two. The distance of the two is D(t)=||x0(t)-x1(t)||. The minimum distance is at d/dt D(t) = 0. Derive and resolve t (excluding any special cases of zero velocity and such here):
D(t) = sqrt((p0x-p1x+(v0x-v1x)*t )^2 + (p0y-p1y+(v0y-v1y)*t )^2)
d/dt D(t) = 1/sqrt((p0x-p1x+(v0x-v1x)*t )^2 + (p0y-p1y+(v0y-v1y)*t )^2) * (2*(p0x-p1x+(v0x-v1x)*t )*(v0x-v1x) + 2*(p0y-p1y+(v0y-v1y)*t )*(v0y-v1y)) = 0
(p0x-p1x+(v0x-v1x)*t )*(v0x-v1x) + (p0y-p1y+(v0y-v1y)*t )*(v0y-v1y) = 0
(p0x-p1x)*(v0x-v1x) + (p0y-p1y)*(v0y-v1y) = -t * ((v0x-v1x)^2+(v0y-v1y)^2)
t = -((p0x-p1x)*(v0x-v1x) + (p0y-p1y)*(v0y-v1y)) / ((v0x-v1x)^2+(v0y-v1y)^2)
This gives you the time t at which the distance of the two objects is minimal. Clamp t to 0-1 (for the duration of 1 frame) and check if D(t) is smaller than the sum of the two sphere's radius.
(math not double checked, but you should get the point)
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